The present disclosure relates to signal transmission/reception, and more particularly, to a method for Cellular Text Telephone Modem (CTM) operation with sampling rate conversion, and a related machine readable medium.
A text telephone (TTY) is one of the most commonly used applications by people who are not capable of communicating orally/aurally over the telephone. TTY is a device that uses texts (text signals) instead of voice (speech signals) to communicate over a telephone network. This enables people with hearing or speech difficulties to converse on the phone by typing messages; the signal generated by TTY is then transmitted to a Cellular Text telephone Modem (CTM) which allows a reliable transmission of text characters via the speech channel of a cellular phone system.
CTM can only work in a narrowband frequency. Conventionally, the signal generated from the CTM for transmission over the telephone network is in a low sampling rate (e.g. 8K), which results in poor communication quality. Thus, one cannot benefit from better communication quality under higher sampling rates.